A strange head porting question....

Moparmal said

OK - so the message Im getting is that if if we were going for 270 cfm from a factory cast head, we'd be better off with a J than a "smogger" - thanks for the replies...

...I asked this because I wanted to make sure that if you were buying some used cast heads to really go wild with, it would still make sense get the best factory design possible to start with -

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If you are talking about 340/360 heads the ports are all the same from the X heads of the late 60's to the smog heads of the late 70's and early 80's. The smog heads are only different in that they have an air injection port and the slight bump in the exhaust port has almost no impact in stock form and is easily removed during porting. The late 80's early 90's 308 heads and the late model magnum heads are the only ones significantly different. 302 heads are a small port head intended for use on a 318.

I don't know if you saw the small block dyno competition in Mopar Muscle but this years competition was small blocks up to 410 cid. They all had to run on the same 93 octane fuel and as with previous competitions there was a points penalty for after market parts meaning the after market parts had to make more power than they gave up in penalty points to be worth while. The folks looking to win the competition all used factory heads.

Now the competitors could use any factory head and do any porting they wanted but could not use epoxy to build up areas and could not use off set rockers. Everyone used magnum heads; no X, J, O, U, 308 or any other factory head. These guys all made 500+ HP with these heads on 93 octane. I would say that pretty much tells you which sb factory head has the most potential.